When you exit out of HKG, do not use the kiosk machine and go to the counter for a return fare ticket for $160 (HKD) from HKG-Kowloon station. When looking at the website, it does day "Customer Service Centres at Airport Express stations or MTR stations" and not the Kiosk machines. I affirm as of March 2003 that the price is correct.
An Airport Express Tourist Octopus Card (the last one shown on the link page below) will only allow you ONE journey on the Airport Express, not a RT journey, for $220.00 and two (2) single Airport Express journeys, a RT journey, for $300.00:
http://www.mtr.com.hk/eng/train/ticket.html
Therefore I recommend the $160.00 RT at the airport and regular single purchases as needed throughout the MTR for a single day in Hong Kong, assuming you plan to use JUST $60.00 for the rest of the city + the Airport Express return included. Remember the STAR FERRY is $2.20 over the harbour and $12.00 using the MTR.
SHADO
[This message has been edited by SHADO (edited 05-26-2003).]